'The Winds of Winter' release date, plot news: George R. R. Martin's writing partners explain the delay for sixth book

The production of the seventh season of HBO's "Game of Thrones" is currently in production and may be aired this summer, but release of the sixth installment of George R. R. Martin's "A Song of Ice and Fire" on which the epic series was based remains unknown.

Fans of the book saga have been expecting to see the sixth book titled "The Winds of Winter" on store shelves since 2011 after the release of the fifth book called "A Dance with the Dragons." But Martin continued his silence about the book's status up to now.

While the 68-year-old author opted not to talk about the status of his upcoming book, his writing partners, Elio Garcia and Linda Antonsson, told Insider that there are reasons why Martin's writing progress for "The Winds of Winter" has been delayed.

According to Garcia and Antonsson, both the process of outlining the plot and the actual "Game of Thrones" series were contributing to the book's delay.

According to Antonsson, using outlines for his plot could not help Martin in progressing with the book. "He feels that once he has outlined it, once he has explored all the details of the story, all the beats of the story, he can't go back and revisit it," she stated. "He experiences the story as he writes it and he wants to be able to surprise himself to some extent or get new ideas along the way."

On the other hand, the writing duo also mentioned that Martin could be affected with all the attention given to "Game of Thrones," since he was also involved in creating the plotline for the TV show. "He loves the people who work on it, he really admires it [...] At the same time I think there's a little bit of 'woulda coulda.' Like if [HBO] just took a bit longer with this maybe he could have caught up," Antonsson also said.

Martin is expected to finally reveal the official release date of "The Winds of Winter" soon.